Pei Xing is a supporting character in the film. Throughout the film, she ages from 8-15. She has a younger-sounding voice from age 8-11 and a more matured one at age 15.

Pei Xing is a prefect at school, hence why she always wears a tie. So she's a more nurturing and calm character because of it. She is concerned with helping out the shy Lucas and helps him come to terms with Zul's passing.

 While she is close to the situation, she never held any resentment from Zul's passing, allowing her to move on quicker than Lucas.